Communication system



Nov. 26, 1940. G, MICHAELSON 2,222,751

COMMUNICATION SYSTEM Filed June 3, 1938 5 Sheets-Sheet l Fig.1.

/ f I III] [I I CIT/3178 5 N l/WfA I'OA" GEORGE MzcHAEbsoN 5, 1940' G.MICHAELSON 2,222,751

COMMUNICATION SYSTEM Filed June 5, 1958 s Sheets-Sheet 2 Fig. 5.

20 51 54' 5 30 Y /65 W l [7 57 /63 H- mv E N TO R GEORGE MIGHAELSON Nov.26, 1940. G. MICHAELSON 2,222,751

COMMUNICATION SYSTEM Filed June 3. 1938 Sheets-Sheet 3 Fig.6.

r r L /63T I8 /50 L \1 l i Z U/ 57 //63 2 24 O 5 N 25 53 4 56 46 48 41 P4] Q L N 60 Mr- I 1 3 4 7 b 58 57 61 2 x 15 I E 6 \NVENTOR GEORGEMICHAELSON ATTORNEYS NOV. 26, 1940. MICHAELSQN 2,222,751

COMMUNICATION SYSTEM Filed June a, 1938 s Sheets-Sheet 4 STE Z480 'INVEN TOR GEORGE MICHAELSON ATTOIW IFKS NOV. 26, 1940. WCHAELSON 2,222,751

' COMMUNICATION SYSTEM Filed June 5. 1938 5 Sheets-Sheet 5 n u-mnwz-wrwa GEORGE MICHAELSO N Patented Nov. 26, 1940 UNITED STATES PATENTOFFICE Application June 3, 1938, Serial No. 211,645 In Great BritainJune 17, 1937 Claims.

This invention relates to telephone systems and to apparatus for use inconnection therewith for the purpose of enabling signals, codes ormessages to be transmitted over the line and re- 5 corded.

The chief object of the invention is to provide a simple and efficientmeans which can be utilised for the purpose of advising a subscriber,upon his return, of the fact that he has been called during 1(1 hisabsence from the home, ofiice or other building in which his telephoneis located.

A further object of the invention is to provide a simple and efficientmeans adapted to insure that, when a call is unanswered, a record willbe made of the callers number and/or his message upon means provided forthe purpose at the calledsubscribers end.

According to the invention each subscriber or certain subscribers is orare provided with means adapted to be brought into operationautomatically or by manually operable means for transmitting along thetelephone line a predetermined signal or group of signals havingcharacteristics which render them capable of being recorded andidentified at the receiving end by a subscriber.

who is not available at the time of the call.

The invention may be carried into efiect in various ways and, in itssimplest form, it comprises means located at the senders end of the lineadapted automatically to transmit over a line a signal or signals whichis or are characteristic of the senders telephone number or tele-,

phone number and exchange and means located at the receivers end forreceiving such signals and making a record of the same.

In the preferred embodiment of the invention, the sending end of theline is equipped with an oscillatory, rotary or other movable memberadapted to influence the character of a series of electrical impulsestransmitted along the line so as to render them characteristic of thatparticular senders identification number or of his number and exchangearea. The aforesaid movable member may be arranged so that it is adaptedto be brought into operation immediately the sender lifts his receiveror after a predetermined delay period. Alternatively, the arrangementmay be such that the movement of the said mem-- ber or the commencementof its movement is un- 50 der the control of the sender. The characterof the impulses may be varied by varying the nature of the movementimparted to the movable member or provision may be made for utilisingdifferent portions of the movable member or of its movement forobtaining the varied impulses.

The aforesaid member may be preformed or shaped to enable the same to beutilised for the purpose in view and may comprise a rotary member ordrum the peripheral surface of which comprises parts having differingelectrical conducting 5 characteristics, e. g. conducting and insulatingparts, formed to correspond with, or to formulate signals whichcorrespond with, the characteristics of the elements or digits of thesignal, telephone number or message to be transmitted.

At the receiving end of the line, there may be provided a record sheetor strip and means such as a marker, perforator or the like forco-operating therewith to produce a record from which the signal ormessage can be identified. For example, means such as a solenoid may beprovided at the receiving end of the line and the arrangement may besuch that each time an impulse is produced at the sending end, thesolenoids will be brought into operation to cause the marker, 20perforator or the like to function. The record sheet or the like mayconveniently be carried by a drum and, if desired, means may be providedfor enabling the drum to be rotated in a step-bystep manner during or atthe termination of each movement of the oscillatory member at thetransmitting end.

In order that the said invention may be clearly understood and readilycarried into efiect, the same will now be more fully described withreference to the accompanying drawings which illustrate diagrammaticallyvarious circuit arrangements suitable for adoption at subscribersstations required to be equipped with means for enabling the inventionto be carried into effect.

Figure l is a schematic View of a portion of a telephone circuitembodying the present invention.

Fig. 2 is a diagrammatic side view of an impulse transmitting mechanism.0

Fig. 3 is a diagrammatic side view of an impulse recording mechanism.

Fig. 4 is a modified form of impulse transmitting and receivingmechanism,

Fig. 5 is a View similar to Fig. 1 of a modified 45 circuit.

Fig. 6 is another view similar to Fig. 1 of a further modified circuit.

Fig. 7 is another view similar to Fig. 1 of still another modifiedcircuit.

Fig. 8 is still another view similar to Fig. 1 of a still furthermodified circuit.

In Fig. 1 of the accompanying drawings, A indicates one side of atelephone transmission line and B indicates the other side thereof. AlsoC indicates the subscribers bell arranged in the usual ringing circuitwhich may be earthed at or as in some cases, may return via the line B.In the ringing or other warning circuit is arranged a pair of relays orelectro-magnetically operable units a and b, one of which is adapted,when energised, to open a normally closed switch whilst the other isarranged so that when. it is energised, it is adapted to attract one endof a switch lever d, which may be normally in the off position, and tocause the same to move about its central pivot and to engage a contact earranged in series with an electro-magnetic device G which forms a partof an impulse recording mechanism. The switch a, theelectro-magnetically operable unit b and the midpoint of the switchlever d are also joined in series by a lead 1 the other end of which isconnected with a suitable point in the subscribers receiver or receivercord 9, or to a convenient point on the line 13. Hence it will be seenthat, upon energisation of the subscribers ringing or warning circuitthe switch 0 Will be opened and the lever d will be moved into contactwith the contact 6, thus allowing the bell C to function in the normalmanner. Immediately, however, there is a pause in the ringing or warningsignal, the switch 0 will close again. In comparison with unit a, theunit b is relatively slow acting with the result that the lever 11 willfor a short period remain in contact with c after the switch 0 hasclosed again. During this period, a circuit through the calledsubscribers receiver, his lead and the electromagnetic device G of hisimpulse recording mechanism is closed and I such circuit is connectedthrough the line and the exchange with the calling subscriber whoseimpulse transmitter is now connected in the circuit through his switch(1 which may be closed by manually operable means. At this stage, thetwo 40 subscribers are interconnected through the exchange in the samemanner as when the line is available for speech currents so that as thecalling subscribers impulse transmitting mechanism is actuated, thecalled subscribers recording 45 mechanism is caused to function forrecording purposes. Hence, it will be seen that the invention providesasimple and convenient arrangement for enabling the ringing or otherwarning current to prepare the called-subscribers circuit arrangement tobe connected, either immediately or through the usual exchangeconnections, with the calling subscriber for transmitting, receiving andfor recording, and to enable the same to be brought into operation forrecording duringthe pauses in the different phases of the ringing orother warning signal so long as the latter is continued. Alternatively,the relays may be arranged and the circuit arrangement varied so thatthe recording circuit is prepared for functioning by 60 the operation ofthe ringing or other Warning signal and the latter prevented fromcontinuing to function until the message has been completed. Accordingto another alternative arrangement, the relays and other elements may bearranged so that the recording is caused to take place at the same timeas the functioning of the bell or other warning signal.

The impulse recording mechanism and the impulse generating mechanism maycomprise a V- shaped or hair-pin like member pivotally mounted at K andhaving an armature I50 and two downwardly extending arms H and Larranged for movement over the surfaces of two rotatably mounted drums Pand Q. The recording arm L 75 may be provided with a suitable markerarranged so that, when this arm is attracted by the electromagneticdevice G and the arm is caused to move out of its normal plane ofmovement, the marker will be brought into contact with a sheet of paperor the like carried by the drum Q.

The drum P may be provided with parts of differing electrical conductingcharacteristics, e. g. conducting and non-conducting areas or strips forthe purpose of enabling the arm H to generate or formulate signals whichare characteristic of the senders telephone number or other signal to betransmitted and, upon the closing of the receivers switch 0, which thussignals the exchange whereupon the usual connections between the twosubscribers are made, the impulses being formulated by the senders drumP and its associated arm H will pass to the device G of the impulserecorder of the called subscribers instrument to actuate the markercarried by the arm L as the latter moves across the strip carried by thedrum Q in synchronism with the movement of the arm H at the callingsubscribers end of the line. For the purpose of enabling the two V-shaped or hair-pin like members to step over the non-conducting areas,each may be provided about its pivotal support with an upwardly and/ordownwardly extending arm terminating in an adjustable weight W on aspring and the said arm or another arm coupled therewith may be utilisedas the armature of an electro-magnetically operable device consisting,as shown in Fig. 1, of two electro-magnets F and F which are also soarranged and connected in circuit that they are adapted to be actuatedby the impulses being generated or formulated by the calling subscriber.That is to say, at the called subscribers end, the impulse recorder andthe electro-magnets Fand F are connected for intermittent operation inseries with the line that carries the impulses being formulated by thecalling subscriber, the said electro-magnetsbeing actuated alternately.The movements of the mass W allows its equivalent mass L time to changeits plane of oscillation and enables it to rise and fall relatively tothe paper or the like on the drum Q. This arrangement also ensures thebreaking up of a magnetic pull into several stages corresponding to theconducting and insulating areas which are included in the circuit.synchronisation is also ensured by arranging the circuit as shown sothat the pull of the electro-magnetic device G on the arm L issimultaneous with the action of the electro-magnet F or F on thearmature I and persists as long as the calling subscribers arm H istraversing one of the conducting portions of his drum P.

In Fig. 2 of the drawings there is shown diagrammatically a side view ofthe impulse transmitting mechanism shown in Fig. 1 and Fig. 3 showsdiagrammatically a side view of the impulse recording mechanism. In thearrangement shown in-Fig. 1, the drums P and Q are adapted to be rotatedby a toothed or ratchet wheel N disposed intermediate the ends of arotary memher which incorporates the two drums. If desired, however,this arrangement may be replaced by one in which the two drums areadapted to be rotated by a toothed or ratchet wheel disposed at one endof one of the drums as is shown, for example, in Fig. 4, the arrangementbeing such that the ratchet wheel N is adapted to be rotated step bystep by a pawl associated with the armature 4 of an electro-magneticallyoperable device 5. The latter may be connected in circuit with aflexible contact device 1 arrangedso that the lever H or L contacts withthe contact deviceat the beginning or end of its swing and so energisesthe electro-magnetically operable device 5 to attract the armature 4 andto thus turn the ratchet wheel through one step.

Referring now to Fig. 5 of the accompanying drawings, it will be seenthat the subscribers bell C is arranged in the usual ringing circuit andthat a ringing tone circuit is provided across the lines A and B by theconductors IBI, I62, I63, I64 and I65. Included in said circuit, is theelectromagnetically operable unit b adapted, when energised, to attractone end of the switch lever d pivoted at 8 and adapted when soattracted, to engage the contact e. The latter is connected by aconductor I2, which includes an A. C. relay E, with another contact I4which is normally engaged by a switch lever I5I which is in turn,connected by a conductor I5 to the pivotal mounting I8 of an impulserecording mechanism which is similar in many respects to that describedabove in that it comprises a V-shaped or hair-pin like member pivotallymounted at I8 and having two arms H and L arranged for movement over thesurfaces of two rotatably mounted drums P and Q. The recording arm L maybe provided with a suitable member arranged so that, when an armature 20is attracted by an electro-magnetic device G, the arm will be caused tomove out of its normal plane of movement and the marker will be broughtinto contact with a sheet of paper or the like X carried by the drum Q.

The mechanism also includes a weighted lever .or pendulum W (which ispreferably flexible or resilient) depending from the pivotal mounting I8and arranged for movement with the V-shaped or hair-pin like member andthe lower end of the pendulum is provided with an extension serving as acontact 24 for engagement with a switch member 25 which may convenientlyconsist of a disc or ring-like element provided with a circumferentialcut-away portion or recess and suitably biassed so that one side of thecut-away portion bears against the extension of the pendulum. Thebiassing may be accomplished by suitably weighting the switch member orby mounting the same eccentrically or by other means. I'hrough themedium of the pendulum and its contact 24, the conductor I5 iselectrically connected with one side of the said cut-away portion whichis con nected by a conductor 26 with an electro-magnetic device F andthe latter is connected with the other side of the line B.

Hence, it will be seen that upon contact being established between theswitch lever d and the contact e, a circuit is completed throughtheconductor 30, switch lever d, A. C. relay E, switch lever F, pendulum Wand electro-magnet F to the line B and current traversing this circuitwill energise the electro-magnet F thereby attracting its armature I50.The latter is pivoted at I8 and interconnected with the hair-pin likemember so that the arm L is swung to one side of the sheet of paper Xready for operation.

It will also be observed that fromthe contact 6 is arranged a circuitparallelling that containing the A. C. relay E, the switch lever I5I andthe conductor I5, said circuit including a switch 34 adapted to beclosed by the relay E, a relay 35 for opening the switch I5I and theelectro-magnetic device G. Hence, when an alternating or pulsatingcurrent derived from the exchange or senders apparatus traverses thecircuit containing the A. C. relay E, the latter will be actuated toclose the switch 34 and the marker will be brought into its markingposition. Also, by virtue of the energisation of the relay 35, theswitch I5I will be actuated to open the direct current circuit throughF.

Each subscriber is provided with an impulse generating device forformulating impulses which are characteristic of his telephone number orother signal to be transmitted and this device may comprise a drum Pprovided with a central continuous conducting strip or ring and with twoend continuous conducting strips or rings 4| and the intermediateportions may be formed with conducting and insulating areas or stripswhich are so arranged that, by the movement of the arm H thereacross insynchronism with the movement of called subscribers' recording arm L,impulses which are characteristic of the senders telephone number andexchange lettering or other signal to be transmitted are formulated.Intermittent movement of the drums P and Q is adapted to be broughtabout by a pawl and ratchet wheel N or other suitable means such asisdescribed above through the actuation of the electro-magneticallyoperable device 5 brought into operation at the end of each swing of themarking arm L. When impulses are to be transmitted over the line, theswitch lever d is moved by automatic or manually operable means so thatits upper end is brought into contact with the contact 46 which isconnected with the drum P through an A. C. relay 48.

From the foregoing it will be seen that when the lower end of the switcharm d at the called subscribers station is in contact with the contacte, a D. C. circuit is closed through the switch I5I and theelectro-magnet F. The current for this circuit may be derived from thecentral exchange or from a local source or battery adapted to be broughtinto operation by an exchange current and when this current is availableand utilised for the actuation of the magnets F and the consequentdisplacement of the hair-pin like members, the pendulums W Will also bedisplaced in opposition to the .biassing means associated with theswitches 25 and the arm H will be moved from contact with the conductingzones 40. The momentum of the pendulum device is sufficient, however, tocarry the calling subscribers arm H over the nonconducting area tocontact with the next conducting area formed, e. g. by one of the digitsof the telephone number, with the result that the calling subscriber'smechanism formulates impulses varying in character with the nature ofthe telephone number, which impulses intermittently actuate the device Gat the called subscribers instrument for efiecting the recording. Thusthe circuits including the relays E and 35 will come into operationalternately as the calling subscribers arm H is advanced across theimpulse formulating drum. In this way, the switches 25 are eventuallybrought into a position in which the biassing means causes the contact24 to be broken and the opposite side of the recess of the switchcontacts with the pendulum device to bring the other electro-magnet Finto operation with the result that movement of the hairpin like membersand the pendulum device will be reversed. In the arrangementillustrated, an armature 5| is attached to the recording arm L and 52 isa contact carried by the switch 25 for engagement with a relativelyfixed stop and contact 53. When the contact 24 has swung its full periodto the right the electromagnetic unit 5 operates to hold the armature 5|in position also the member 55 carrying the pawl associated with theratchet wheel N. Also, when the calling subscribers arm H reaches thecorresponding position the contacts 24. and 52 and the contacts 52 and53 on his instrument will make and/or break and thus send across theinductive coupling a pulsation to operate the relay E at the calledsubscribers instrument. The relay 35 is thus brought into operation toopen the circuit i5, 55, f 54, 53' and to de-energise the unit 5 torelease armature 51 to enable the hair-pin like member to swing back andalso to release armature 4 to rotate the drum Q. If the callingsubscribers arm H arrives first and is held, through its arma- 173 ture5| by its electro-magnet 5 the subsequent arrival of the calledsubscribers arm L andthe make and/or break operations will send back itspulsation to be received by the caller, via conductor 3i), 8, 45, 48opening 58 and thus restoring electromagnet 5 and securing synchronismfor the rotation of the drum.

It will be observed that when the electromagnetic unit b is actuated tocause the switch lever 01 to engage with the contact 6, it has the sameeffect for completing subscribers loop as if the receiver had beenlifted and this flashes a signal to the exchange to connect the twosubscribers in the usual way. On completion or" the message, therelatively conducting and insulating areas will flash the clearingsignal.

The invention can be adapted to various forms of transmission lines orcircuits whether wired, inductively coupled or radio-linked, the number,position and character of the various electrical units, e. g.inductances, relays, capacities and the like, incorporated in the systembeing varied to suit the individual requirements. For example, in orderto carry into effect some of the objects of theinvention, -e. g. thetransmission reception .40 and/or recording of electrical impulses, whenthe operator is not available, over a metallic and/or an inductivelycoupled line or circuit including radio-linked means of communication,the switch lever 34 may be arranged so that it is A5 normally inengagement with its contact, and

the switch lever I5| may be arranged to be normally free from itscontact M (as is shown, for example, in Fig. 6 of the accompanyingdrawings) With such an arrangement when the bell 50 (or other warningdevice) current or impulse operates the relay 1) battery current willfiow from the line A, through 30, b, 8, d, e, 34, 35, G

and back via the B line. The relay 35 will then operate the switch leverl5l and battery current 55 will-flow through e, 12, E, [4, HM, I5, l5,W,24, 25,

F and back via the B line, both F and G functioning.

Now, if the partsH and P of the calling device are in metallic circuit,every time the part H 60 breaks circuit in the calling device, thedevices G and F restore in the called device.

But when the two devices are inductively coupled then the interruptionsof contact through H and P in the calling device are received as ($5pulsations, or alternating current impulses by E, which opens 34,restores 35, opens l5! and both F and G at the called end restore.

Thus'the lateral movements of the respective hair-pin members aresynchronised and the 70 sendersmakes and breaks are registered by thecalled subscribers device in the proper order.

As shown in Fig. 6, for synchronising the rotarymovements of the drums,or the sliding and the like movements of any of the other displacea'ble75 elementsyin botha metallic and a non-metallic circuit, theelectro-magnetic device 48 in the caling device may be aD.C.magnet andbe connected through a normally closed switch lever 53 to the drum P.The device 48 controls a normally open switch lever 58 in circuit withan A. C. relay controlling the switch lever 65. Also, 53 may be aflexible or a relatively movable contact, and 4! may be a relativelylarge conducting area. Thus, in the calling device, the upper part ofarm (1. having contacted with 46, D. C, current operates F then F, until24 contacts 52 and 53 being movable or otherwise, offering a means ofrelative long contact battery current will flow from the A line through8, 46, 48, 6B, 4!], 41, H, l8, W, 24, 52, and F to the B line. At thesame time, battery current will also flow through 45,58, BI, 57, 55, 54,53, 52, F, B line, B line in the called device, F, 52, 53, (if 52 hasalready arrived to contact with 53) 54, 51, 56, I5, I5l, E, l2, 6, d, 8,b and 35 to A line. The electromagnetic device 5 then operates to hold 4and/or 5|, until W swings back and breaks and/or reverses the contacts.If 52 reaches 53 in one device in advance of the other, 5 cannot operatebut a period of waiting is provided for, by 4| H in the calling deviceand 52 and 53 in the called device.

When the devices are coupled inductively or radio-linked then when 52reaches 53 in either device 5 will hold 5|, and 4 until a make and/or abreak pulsation is received from the other device to operate in thecalling device 51 open 60 restore 48 and open 58 thus restoring 5 and inthe receiving device the pulsation operates E opening 34, restoring 35and opening [5| thus, too, restoring 5, the pulsations operating bothways.

In the above arrangements, the unit b may comprise an A. C. and/or a D.C. relay suitable both for causing d to engage with its proper contactand to hold the same engaged. Also, in some instances, a photo-cell orsimilar device may be provided for the purpose of engaging d and itsassociated contact.

Means may also be provided for marking or recording incoming and/oroutgoing calls. For example, the G unit and 35 may be connected with acontact that is brought into circuit only when the arm H and/or the armL or other movable element reaches that contact.

Means may also be provided for registering only the effective calls,whether incoming or outgoing, irrespective of whether the device is inuse at the other end or not. lead may be taken from G and 35 to acontact disposed between 52 and 53 and this contact arranged to bebrought into the circuit only when 52 is caused to engage with 53.

Also, the recording drum or sheet X may be provided with numbergraduations to facilitate the reading of the registration or checkingmarks. If desired, an alarm signal or warning mark may be associatedwith X or elsewhere for indicating or warning of the approach of acondition in which the marking means needs attention.

In its preferred form, the invention also includes means for enabling acalling subscriber to determine or be advised as to whether the correctnumber has been obtained and said means may be actuated or adapted to bebrought into actuation by mechanical or electrical means. For thispurpose, each of the drums P may be arranged so that it is capable ofbeing adjusted angularly and each drum may carry a cam or othermeanscapable of establishing contact at 45 and breaking the contact between(1 and e For the purpose, 2.

once the unit b has brought d and the cam within reach of one another.Thus, when the calling subscriber lifts his receiver and obtains anumber, he will be able to hear the clicking sounds or notes produced bythe functioning of the called subscribers device and on the approach ofthe signalling section of the device (which may be preceded by specialinterruptions on the drum) he can switch-in his device (if necessaryafter 10 adjustment) to have the called number marked on his recordingelement X. If this number should be the wrong one he then may have itcancelled in the usual manner.

Referring now to Fig. 'lof the accompanying 15 drawings, it will be seenthat the subscriber's bell C is arranged in the usual ringing circuitand that the subscriber's circuit includes a device 200 incorporatingsensitive pivotally mounted pointer or', switch 205 which normally restsagainst a 20 relatively fixed contact 20! and which, upon displacement,is adapted to engage another relativey fixed contact 202, the pivotbeing connected with one side (e. g. the side A) of the transmissionline. Associated with the device 200 are an ear piece 206 and amicrophone 201, the latter being arranged in close proximity to theformer and being connected in circuit so that pulsations received by theear piece will affect the microphone to cause the latter to influencethe device 30 200 in such a manner that the pointer or switch 205 willbe caused to be displaced from the contact 20l, towards or to thecontact 202, such movements being in sympathy with or forming areproduction of impulses received over the line. If desired, a battery89 or other source of local current may be arranged in circuit with thedevice 200 or the apparatus.

In one side (e. g. the side 3) of the line is arranged the coil of aslow release relay b 40 adapted, when energised, to displace the switchmember (1 pivoted at 8, said member in this embodiment comprising threearms indicated at d,

dl and d2.

The subsoribers station also includes an im- 45 pulse recordingmechanism which is similar in many respects to those described above andcomprises a V-shaped or hair-pin like member pivotally mounted at l8 andhaving two arms H and L arranged for movement over the surfaces 0. oftwo rotatably mounted drums P and Q. The

recording arm L may be provided with an armamm 20 opposite which isdisposed an electromagnetic device G which when energised will cause thearm to move out of its normal plane 55 of movement so that a marker M orthe like provided at the end of the arm will be brought into contactwith a sheet of paper or the like X.

carried by the drum Q. The electromagnetic device G is preferablycarried by means also 60 pivotally mounted at l8 and adapted to moveabout the pivot in synchronism with the arm L. As will hereinafterappear, the arm L is adapted tobe moved about the pivot l8 to cause themarker or the like to move across the paper 65 X and the arrangement ispreferably such that the arm is displaced in one direction (e. g. to theright) by the actuation of an electro-magnet F when it attracts anarmature I50 carried by the aforesaid V-shaped or hair-pin like memberand 70 is adapted to be displaced in the opposite direction under theinfluence of gravity. During the periods when the arm is required to bemoved by gravity, it may be desirable to provide means for arresting itsmovement about the pivot l8 whilst 75 the marker is in contact with thepaper and, for

this purpose, there may be provided adjacent the opposite end of theelectro-magnetic device G which end may be slow to release, alfixed butflexible metallic member adapted, upon energisation of G, to beattracted andflexed by G in such 5 a manner that both G and the arm Lwill be momentarily prevented from movement about the pivot l8.

The aforesaid drum P forms part of an impulse generating device forformulating impulses 10 which are characteristic of a telephone numberor other signal as is described above, the said drum is provided withconducting and insulating areas or strips which are so arranged, that bythe movement of the arm Hthereacross in synchronism with the movement ofcalled subscribers recording arm L, impulses which are characteristic ofthe senders telephone number and exchange lettering or other signal tobe transmitted are formulated.

Synchronism of the respective markings at one end of the line with thecorresponding impulses generated at the other end is brought about bythe functioning of the respective relays and their associated contacts,and the consequent functioning of arresting means for the arms H and Las hereinbefore described. Intermittent movement of the drums P and Q isadapted to be brought about by the pawl and ratchet wheel N or othersuitable means such as is described above through the actuation of theelectro-magnetically operable device 5 brought into operation at the endof each swing or during the swing in either direction of the marking armL. When impulses are to be transmitted over the line by 30 the callingsubscriber, the switch lever d3 is moved by automatic or manuallyoperable means so that its lower end is brought into contact with theupper end of the lever dl, and dl swings so that d is contacted with 46or c.

It will be seen that, when a subscriber is called, alternating currentcan pass from one side of the line, e. g. A through the bell or otherwarning device C, capacity C and the coil of the slow release relay 1)to the other side of the line.

The effect of such a ringing current through b is to cause the switchlever dl to be swung about the pivot 8 to the left and also to close theswitch 4. Closing of switch 204 by-passes b and allows the bell to ringwithout deleterious effect. 50 Also, by the movement of dl,the lever dwill be raised to engage either a contact e or a cam 40 carried by theshaft carrying the aforesaid drums. When the lever d contacts with thecontact 6 or with the cam 46, the circuit is completed through conductor15, contact strips 82 and 83, arm H, plate 225, and the coil of theelectro-magnet F" to the other side of the line, thus providing a pathfor alternating current or pulsations.

The ringing current is now capable of influencing device 200 and itssensitive element 205, which will move to contact 202, and a solenoid Ewill operate closing by-pass switch 86 to form a path for D. C. and thustrip the ringing current circuit. (E may be of an inductance and/orresistance that will allow ringing current to continue functioning.) Thecalling subscribers can now hear the called station apparatus functionand may operate his switch d3 to start his apparatus and receive and/ortransmit signals. Solenoid E may also be slow to operate and thus switchelement 205 may have to be moved to 202 more than once to close 86.Alternatively, it may be arranged, e. g. in metallic circuits, for theringing current to continue until the calling sub- 40 the line.

scriber realising that the called subscriber is not answering operateshis impulse transmitter or closes his switch (13 to bring histransmitting apparatus into operation. By the act of switching at thecalling subscribers end of the line, the ear piece 295 and microphone281 at the called subscribers station as well as those at the callingstation if so equipped will be brought into operation so that thesensitive pointer or switch element .205 will be momentarily swung intocontact with the contact 202 to close direct current circuit from oneside of the line (e. g. A), through 255, contact 252, a slow releasesolenoid E, conductor 9!, electromagnetic device G and conductor 92 tothe other side of the line. Thus the solenoid E is brought intooperation to hold the levers d2 andd tilted with the latter in contactwith as or s. Also, by the operation of E, switch 85 is actuated toby-pass condenser 85 at the called station and thus closing another D.C. circuit and by the operation of G, the armature 29 is attracted tocause the marker M to be brought into contact with the paper X. Havingthus set up the D. C. circuits referred to and as soon as switch element205 returns to contact with 251, the direct current passing through E"operates the latter to cause H and L to swing to the right about thepivot Hi, the swinging movement continuing until L reaches its otherextreme position.

Shortly before the marking arm L reaches the end of its swingingmovement to the right, contact takes place between an element 52 carriedby the arm, a switch 58 and a contact 53 with the result that thecircuit is closed from A through M5, 25!, switch 85, lever d, conductorsl2 and i5, conductor 56, coil 54 of the electromagnetic device 5,contact 53, switch 58, coil of the electro-magnetic device 19 to theother side of Electro-magnetic device is thus operated and attracts thearmature 5| on the arm L and is at this stage of the operation in closeproximity to the device 5. Also, the downwardly extending portion of theelectro-magnetic de- 45 vice 5 attracts the armature 4 which is providedwith a one way flexible pawl engaging the ratchet wheel N so that thelatter becomes turned through one step. In the meantime the arm H hasseparated from the contact device 25 and discon- 50 nected contactstrips 82 and 83. At this stage, whether the senders arm L has alreadyreached a corresponding position at the other end of the line or isstill lagging the hair pin like member arriving first will be heldwaiting by the direct current solenoid until the slow actingelectromagnetic device l3 operates to close the switch 18 and theimpulse thus produced at both or first at one then at the other endcauses. the element 205 to be displaced and to break the circuit at 25!.Thus the commencement, the stepby-step movements during, and/or theending of each swing, and the angular displacement of the drum, aresynchronised. The switch 25 is nex ibly mounted so that the part thereofwhich carries the contact strips .82 and 83 is slightly inclined to theplane of oscillation and a bent L- shaped projection carried by the armH is able to contact with the contact strips 82, '83 on one side of theswitch 25 when the hair-pin like-mem- 70 her is moved to the right andwith the contact strip 25 on the other side of the switch 25 whenfalling back under the action of gravity to the commencing position]Thus, when the hair-pin like-member released by the electro-magnetic de-75 vice 5 is falling back, the arm H engaging with the drum P closes acircuit from one side of the line e. g. A through 255, 2!, conductor 30,switch '86, drum P, arm H, contact 28 on the underside of 25 and back tothe other side of the line. As mentioned above, the surface of the drumP is made up of insulating and conducting areas preferably flush withone another and with the rest of the drum, according to the outline ofthe signal to be transmitted and as the arm H passes from a conductingto an insulating portion and vice Versa, impulses are formulated, saidimpulses actuating at the senders and/or the receivers end the relaycomprising the ear piece and microphone device and th deviceincorporating the pointer 0 so that in turn the pointer 205 is caused tomove and contact With the contact 262 which again enables a current tooperate the electro-magnetic device G and to cause the markings to beproduced upon the paper X. In this manner, X receives a series ofmarkings corresponding in position from right to left with the positionof the respective insulating and/or conducting areas provided on thesenders drum P, which are continued in succemive lines with the step bystep rotation of the respective drums. Shortly before the hair pin likemember reaches the end of its movement to the left, the solenoid 93 willbe operated to raisethe armature 32 which is now in proximity to thesolenoid, to cause the contact to be broken at 25 and to dis place thearm H beyond its normal position. When, however, solenoid 93 restoresand permits the arm H to be restored to its former'position of contactwith strips 82 and 83 arm H will again serve to close the circuitthrough the electromagnetic device F.l. If desired, the paper X may reston a support so that the marker M is at a constant distance from X forensuring the effective striking of the same irrespective of anyvariations in the diameter of the roll of paper.

- It will be appreciated that the device incorporating the switchelement 2B5 and the contacts and 202 may comprise one or more rigid orflexible contacts for making and/or breaking and/or by-passing circuits.Also, more. than one switch element 255 may, in some instances, beprovided and arranged so that each functions under different conditions.For example, one such element may be provided and arranged so that itnormally contacts with 20! when the bellis ringing and moving to contact2B2 with the variations of the bell current and another such pointer maybe provided and arranged so that it normally contacts with the contactand moving to contact with its contact 262 with the formulation andreception of the signals after the bell has stopped ringing.

In Fig. 8 of the accompanying drawings there is shown a circuitarrangement which is similar in many respects to that shown in Fig. '7and in which corresponding elements are denoted by correspondingreferences. In this arrangement, however, there is introduced adelay-action means adapted to afford the called subscriber when he isavailable, the opportunity of; or a" longer period for, answering thecall before the recording mechanism is: brought into operation. Also,the said means may'afford the calling subscriber the opportunity ofhanging up his receiver before the termination of the ringing period.For the purpose of introducing such a delay a plurality of switches oroscillatory members is used and arranged so that for a period theyoperate in out-of-phase :relationship and only when the said switches'or oscillatory -members become in phase or otherwise coincide orco-operate will the circuit for initiating the operation of therecording means be completed. For example, the device 200 may beprovided with a further contact 2I0 arranged so as to be engaged by theswitch element 205 at the time the latter contacts with the contact 202.Also, across the contacts 2I0 and 202 is arranged a circuit including alocal battery I00 and an electromagnetically operable device 94 which,when actuated is adapted to attract one end 99 of a lever or pendulumdevice 91 mounted for movement about a pivot 95, the lower end of thesaid device being provided with a contact I03 for engagement withanother contact 96 connected with the slow release solenoid E. The leveror pendulum device is preferably provided with an adjustable ordisplaceable weight 9'! so that its period of oscillation relatively tothat of another switch, pointer or lever, e. g. the element 205, can bevaried. Thus, when the ringing or warning bell C is actuated, theelement 205 will be swung into contact with the contacts 2| 0 and 202and local circuit through contact 2I0, battery I00, device 94 and othercontact 202 will be completed, with the result that the electro-magneticdevice 94 will be brought into operation to attract the upper end 99 ofthe lever or pendulum 91. The lower end I03 of the lever or pendulum isthus caused to engage with the contact 06 which is connected with theslow release relay E for establishing a circuit through E, 8, d, e, I5,82, H, 83, 93 and the line B. It will be seen that the pivot 95 of thelever or pendulum 91 is interconnected with the contact 202 and that itis not until the contacting of 202 and 205 coincides with the contactingof I03 and 96 that the relay E will be brought into operation to closethe switches 86 and 98 for establishing the ap- 0. propriate D. C.circuits. Hence, by suitably varying the difference between the periodof oscillation of the element 205 and that of the lever or pendulumdevice 97, the delay period can be increased or decreased. It will alsobe seen that,

45 in this arrangement, inter-action between the microphone 201 and theear piece 1 is increased by the inclusion of an inductive coupling ortransformer I08.

Having thus described this invention what I claim as new therein anddesire to secure by Letters Patent is:

1. A telephone system having a plurality of subscribers stations eachequipped with means for formulating and transmitting over the lineimpulses constituting a recordable signal and recording means arrangedto be brought into operation at a called subscribers station forreceiving and recording the signal of the calling subscriber, the saidimpulse formulating means and recording means comprising a double-armedmember constituting an impulsing arm and a recording arm arranged formovement over the surfaces of a pair of rotatably mounted drums, one ofthe said drums being formed with conducting and insulating areascontoured and arranged for scanning by the impulsing arm to produce apredetermined signal and the other drum being equipped with a recordelement for cooperation with the recording arm, and the arrangementbeing such that by the relative displacement of the drums and thedouble-armed member, the impulsing arm at the calling subscribersstation opens and closes the circuits for the transmission of thepredetermined signal while the recording arm at the called subscribersstation is moved across and to and from the record element at the latterstation to record the impulses transmitted.

2. A telephone system as claimed in claim 1 provided withelectro-magnetically operable means for effecting a step-by-stepdisplacement of the double-armed members relatively to the drums at thecalling and called subscribers stations.

3. A telephone system having a plurality of subscribers stations eachequipped with means for formulating and transmitting over the lineimpulses constituting a recordable signal and recording means arrangedto be brought into operation at a called subscribers station forreceiving and recording the signal of the calling subscriber, the saidimpulse formulating means and record ng means comprising a double-armedmember at each station, one arm of the doublearmed member forming animpulsing arm and the other arm forming a recording arm, eachdouble-armed member being arranged for oscillatory movement relativelyto the surfaces of a pair of drums, one of said drums being formed withconducting and insulating areas contoured according to thecharacteristics of the signal to be transmitted and the other drum beingequipped with a recording element with which the recording armcooperates, and electro-magnetically operable means for impartingstep-by-step rotary movements to the drums at the end of each swing ofthe double-armed members.

i. A telephone system having subscribers instruments equipped with meansfor formulating and transmitting over the line impulses constituting arecordable signal, which signal is characteristic of the telephonenumber of the calling subscriber, and recording devices arranged to bebrought into operation during the absence of a called subscriber forreceiving and recording the signal of a calling subscriber, the saidimpulse formulating means comprising a contact member movable inrelation to a displaceable element and the said displaceable elementhaving parts of differing electrical characteristics contoured accordingto the nature of the signal to be transmitted, said subscribersinstruments being fitted with a sensitive pointer arranged in circuitwith a receiver or ear piece disposed in close proximity with amicrophone whereby pulsations received by the receiver affect themicrophone to cause the pointer to move in sympathy with the impulsesreceived for the purpose of setting up the circuits required forrecording such impulses.

5. A telephone system having a plurality of subscribers stations eachequipped with means for formulating and transmitting over the lineimpulses constituting a. recordable signal, the said impulse formulatingmeans consisting of a contact member movable in relation to an angularlydisplaceable drum and the said drum being made up of relativelyconducting and non-conducting areas contoured according to the nature ofthe signal to be transmitted, and recording devices arranged to bebrought into operation at a called subscriber's station for receivingand recording the signal of the calling subscriber, said subscribersstations each being fitted with a sensitive pointer, a receiver orear-piece arranged in circuit with the sensitive pointer and amicrophone disposed in close proximity with the receiver or ear piecewhereby impulses received by the receiver affect the microphone to causethe pointer to move in sympathy with the impulses received for thepurpose of setting up the circuits required for recording said impulses.

6. A telephone system as claimed in claim provided with a delay actionmeans for introducing a delay in the setting up of the signaltransmitting and receiving circuits.

7. A telephone system as claimed in claim 5 provided with a delay actionmeans consisting of a plurality of oscillatory members arranged tocontrol the closing of the signal transmitting and receiving circuits,the arrangement being such that only when the said members are in phasewill the circuits for initiating the actuation of the signaltransmitting and receiving means be completed.

8. A telephone system having a plurality of subscribers stations eachequipped with means for formulating and transmitting over the lineimpulses constituting a recordable signal, the said impulse formulatingmeans consisting of a scanning device movable in relation to an'angularly displaceable drum and the said drum being made up ofrelatively conducting and non-conducting areas contoured according tothe nature of the signal to be transmitted, and recording devicesarranged to be brought into operation at 2. called subscribers stationfor receiving and recording the signal of the calling subscriber.

9. In a telephone system, a calling station including means forformulating and transmitting electrical impulses, saidimpulse-formulating means comprising a scanning device including acontact member, an angularly displaceable drum having on its surface asignal outline, said signal outline being made up of relativelyconducting and non-conducting areas contoured according to the nature ofthesignal to be transmitted, means for causing the contact member totraverse the surface of the drum whereby each point on the surface ofthe drum is brought into drumhaving on its surface a signal outline madeup of relatively conducting and non-conducting areas'contoured accordingto the nature of the signal to be-transmitted, means. for moving saidcontact member back and forth over the surface of the drum, means forrotating said drum to bring each point of its surface in turn beneaththe contact member, means for transmitting over the line point-by-pointimpulses produced by contacts sequentially established between thecontact member and the conducting parts of the signal outline, and acalled station including means for sequentiallyrecording said impulsesto re-formulate point-by-point the signal outline.

GEORGE MICHAELSON.

